Treatment of hydrocarbon oils



Patented Nov. 14, 1933 mm STA E :1,935,161 1 TREATMENT or HYDROCARBON OILS Jacque C. Morrell and Gustav Egloff, Chicago, 111., assignors to Universal Oil Products Company, Chicago, Dakota No Drawing.

111., a corporation of South Application January 29, 1931 Serial No. 512,208

1 Claim. (01-196 36) This invention relates tothe treatment of hydrocarbon oils, and refers more particularly tov the refining of the relatively low. boiling hydrocarbon distillates. 1

In one of its specific aspects the invention embodies a process for refining cracked hydrocarbon oils and comprises subjecting such oils to treatment with sulphur trioxide and steam in the presence of a metallic oxide. g r The invention has'especial application to the refining of the lighter hydrocarbon distillatesin the vapor phase and is particularly useful in the refiningin'the vapor phase of the relatively low boiling products resulting from theconversion of hydrocarbon oils by subjecting the said vapors from the cracking process during or subsequent to fractionation to treatment with sulphur trioxide and steam in the presence of a metallic oxide.

The usual method of refining cracked distillates is to subject them to treatment with sulphuric acid and alkaline solutions, including plumbite solutions consisting of litharge dissolved in alkaline solutions in various combinations of treatment and subsequently to subject the acid treated product to redistillation' usually in the presence of steam. The present invention permits the direct treatment of the hydrocarbon vapors from the cracking process, reducing the cost of reagents and eliminating the redistillation or rerunning operation, although it is within the scope of the invention to revaporize the product in a subsequent operation and subject the vapors to treatment as described. 7

Among the metallic oxides which may be used and as examples thereof are the following: The

oxides of calcium, magnesium, aluminum, zinc, tin, iron, copper, lead, mercury, cobalt, nickel, chromium, manganese, molybdenum, vanadium, tungsten, and the like. It is within the scope of the present invention to employ mixtures of the metallic oxides.

In applying the process of the invention to practice any suitable equipment may be employed which will permit the contacting of the hydrocarbon vapors and the sulphur trioxide and steam treated in the manner described.

with steam is introduced into the tower.

may be introduced directly intothe tower or treating vessel containing the metallic oxides. In lieu of direct packing of the tower or treating vessel with the metallic oxides an inert filling material such as Raschig rings, firebrick, crushed rock, gravel, crushed ceramic material, and the like, suitably coated with a metallic oxide, or a mixture of the same may be employed. Similarly, any device which permits the efficient contacting of the vapors undergoing treatment with the metallic oxide may be employed.

The tower or. treating vessel containing the metallic oxides may be directly connected to a cracking unit or to a rerun, or redistillation unit so that the vapors arising therefrom may be 7 It has been found desirable to neutralize the distillate immediately after condensation either by passing the condensate directly through a body of alkaline material such as a solution of caustic soda or by washing the distillate free of sulphur trioxide with water and/or alkalies, such as a solution of caustic soda, ammonia, or the like. The neutralizing agent may also be introduced into the vapor line leading to the condenser or into the condenser itself.

The amount of sulphur trioxide employed may vary from a fraction of a pound to several pounds,

based on a barrel of hydrocarbon distillate treated.

Various temperatures of treatment may be employed, for example, from 250-600 F. more or less, and the pressures may be sub-atmospheric, atmospheric, or superatmospheric. While the results may vary with the temperatures employed, the pressures and temperatures are chosen so that the hydrocarbons are treated substantially in the vapor phase.

In order to reduce the intensity of the reaction the sulphur trioxide may be admixed with an inert gas such as flue gas, carbon dioxide and the like, and is preferably introduced at various points in the treating tower.

As specific examples of the operation of the 'process of my invention and of the results obtained, at California cracked distillate of approximately motor fuel boiling range is vaporized and subjected to treatment with sulphur trioxide and steam in the presence of zinc oxide. The vapors are passed at a suitable rate through the tower containing the zinc oxide and approximately one pound per barrel of sulphur trioxide together The untreated product shows a gum content of approximately 450 mgs. per 100 cos. and is a reddish brown color. The sulphur content was approximately 0.25. The treated product shows a gum content of approximately 18 mgs. per 100 ccs. and has a color of plus 25 on the Saybolt colorimeter scale. The sulphur content is reduced to approximately 0.16. The gum determinations are made by the copper dish method.

When the zinc oxide is distributed over pumice stone similar results to those just described were obtained.

A mixed Mid-Continent and West Texas cracked distillate when treated in the vapor phase with sulphur trioxide and steam employing iron oxide as a contacting agent gives the following results: The untreated distillate shows a gum content of approximately 350 mgs. per 100 ccs. and a light amber color. The treated distillate may be reduced in gum content to approximately 30 mgs. per 100 ccs. and a color of approximately 30 on the Saybolt colorimeter scale. The sulphur content may be reduced also.

A California cracked distillate when treated with approximately two pounds of sulphur trioxide and steam in the presence of copper oxide shows the following results: The untreated distillate contains approximately 600 mgs. of gum per 100 ccs. The treated distillate may contain approximately 50 mgs. per 100 ccs. The untreated distillate is a dark reddish amber in color, and the treated distillate may have a color from 25 to 30 on the Saybolt colorimeter scale. The sulphur content is quite appreciably reduced.

With a Mid-Continent distillate containing approximately 350 mgs. of gum per 100 ccs. and having a dark yellow color one may obtain a product containing approximately 25 mgs. of

gum per 100 ccs. having a color of approximately 25-30 on the Saybolt calorimeter scale and with an appreciable reduction in sulphur content by treatment with sulphur trioxide and steam employing approximately two pounds per barrel, based on the distillate treated, and using iron oxide as the contacting agent. Similar results may be obtained by employing sulphur trioxide and steam.

The use of tin oxide gives good results when employed as a contacting agent for the treatment of cracked hydrocarbon vapors with sulphur trioxide and steam. Similar results to those shown for zinc oxide may be obtained, but the results vary in degree.

The above examples are only illustrative and should not be construed as restrictions or limitations on the broad scope of the invention.

The treatment herein described may constitute the sole refining action on the oil, or it may constitute one step in a series of refining steps. It may be preceded by the usual treatments with refining agents such as sulphuric acid, caustic soda, plumbite, filtering earth or the like, and may be succeeded by any combination of the above refining agents, followed, if desired, by distillation.

We claim as our invention:

A step in a process of refining the overhead product of motor fuel boiling range resulting from the cracking of hydrocarbon oil, which comprises subjecting said product in a heated vaporous state to treatment with sulphur trioxide and steam in the presence of a metallic oxide.

JACQUE C. MORRELL. GUSTAV EGLOFF. 

